A protester holds up a sign at a demonstration outside McDonald's in Times Square. Photograph: Andrew Kelly/Reuters

Hundreds of fast food workers at New York City branches of McDonald's, Burger King and other big-name chains have staged a walk out in protest of low wages.

The strike, organised by pressure group New York Communities for Change (NYCC), was part of an attempt to gain union recognition for staff at fast food outlets in the city.

"So many people in our neighbourhoods work at fast food restaurants and make poverty wages so low people can't put food on the table, put clothes on their kids' back or even afford the train ride to work," said Jonathan Westin, the organising director of NYCC.

The group staged a number of demonstrations across the city, culminating at the McDonald's in Times Square. Organisers said the campaign would gather pace. NYCC organizers have been holding discussions with employees about forming a new union, the Fast Food Workers Committee, for several months. Attempts have been made to sign them up to a petition demanding that workers be granted the freedom to join a union, and a raise the minimum wage from $7.25 to $15 an hour.

Salon.com reported that a 79-year-old McDonald's employee, who had worked for the chain since 1996 earning $7.40 an hour, was fired after his bosses discovered he was petitioning co-workers. Only three of the 40 employees at his store signed the petition out of fear of losing their jobs.

McDonald's said in a statement: "McDonald's values our employees and has consistently remained committed to them, so in turn they can provide quality service to our customers." It added that most of its franchisees offered competitive benefits.

Some 50,000 workers are involved in the fast food industry across the city, with many paid the median hourly wage of $8.90 (nationally, it is $8.76). Low-pay campaigners estimated in 2010 that an adult with one child living in the least expensive area of the city needs to make $21.85 an hour to be self-sufficient. The average fast food worker in New York earns about $11,000 a year.

Joan Entmacher, vice president for family economic security at the National Women's Law Center, said in an interview with the Guardian that corporations need to see the value in raising the minimum wage. "One of the advantages of raising the minimum wage is that it often lifts the wages for other people, and other jobs that used to be paid a little bit above the minimum wage."

Entmacher said that in raising the minimum wage, corporations would benefit from higher worker productivity.

Westin argued that low pay puts a strain on taxpayers as many workers turn to public assistance to make up the difference. "Taxpayers are footing the bill for what corporations should be paying their workers … It's a huge issue for communities all over the city and all over the country."

Since 2000, fast food employment has grown by over 55%; 19 times faster than the private sector overall. Projections show the growth will jump another 15% by 2018. McDonald's made a profit of $5.5bn last year.

"They're big chains, they're highly profitable, and making their profits off of paying poverty-level wages," said Entmacher. However, many branches are operated on a franchise basis, and owners fear their profitability would be hit if they are forced to pay higher wages than a nearby outlet.